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Biomedical subjects

S Rogers

Publications and source records attributed to S Rogers.

At least 55 records · Page 3Linked to original sources
PubMed2000

Local recurrence after laparoscopic radiofrequency thermal ablation of hepatic tumors.

BACKGROUND: Since we first described laparoscopic radiofrequency ablation (LRFA) of liver tumors, several reports have documented technical and safety aspects of this procedure. Little is known, however, about the long-term follow-up of such patients. METHODS: From January 1996 to February 1999, we performed LRFA on 250 liver tumors in 66 patients. Triphasic spiral computed tomographic scanning was obtained preoperatively and at 1 week, and every 3 months postoperatively. Lesion diameter was measured in the x- and y-axes and the volume estimated; 181 lesions in 43 patients for whom computed tomographic scans available were included in the study. The tumor types were as follows: 64 metastatic adenocarcinomas, 79 neuroendocrine metastases, 27 other metastases, and 11 primary liver tumors. RESULTS: One week postoperatively, the ablated zone was larger than the original tumor in 178 of 181 lesions, which suggests ablation of the tumor and a margin of normal liver tissue. A progressive decline in lesion size was seen in 156 (88%) of 178 lesions, followed for at least 3 months (mean, 13.9 months; range, 4.9-37.8 months), which suggests resorption of the ablated tissue. Fourteen definite local treatment failures were apparent by increase in size and change in computed tomographic scan appearance, and eight lesions were scored as failures because of multifocal recurrence that encroached on ablated foci (22 total recurrences). Predictors of failure include lack of increased lesion size at 1 week (2 of 3 such lesions failed), adenocarcinoma or sarcoma (18 of 22 failures; P < .05), larger tumors (failures, M = 18 cm3 vs. successes, M = 7 cm3; P < .005) and vascular invasion on laparoscopic ultrasonography. By size criteria, 17 of 22 failures were apparent by 6 months. Energy delivered per gram of tissue was not significantly different (P = .45). CONCLUSIONS: LRFA has a 12% local failure rate, with larger adenocarcinomas and sarcomas at greatest risk. Failures occur early in follow-up, with most occurring by 6 months. LRFA seems to be a safe and effective treatment technique for patients with primary and metastatic liver malignancies.

Adenocarcinoma↗
PubMed2000

Gelatinase B (MMP-9) is not essential in the normal kidney and does not influence progression of renal disease in a mouse model of Alport syndrome.

Matrix metalloproteinases are matrix degrading enzymes implicated in many biological processes, including development and inflammation. Gelatinase B (gelB; also known as MMP-9) is expressed in the kidney and is hypothesized to be involved in basement membrane remodeling and in preventing pathogenic accumulation of extracellular matrix in the kidney. Inhibition of gelB activity in metanephric organ culture disrupts branching morphogenesis of the ureteric bud, suggesting that gelB plays a role in kidney development in vivo. We studied kidneys of gelB-deficient mice to search for developmental, histological, molecular, ultrastructural, and functional defects. Surprisingly, no differences between gelB-/- and control kidneys were detected, and renal function was normal in gelB mutants. In addition, gelB-/- embryonic kidneys developed normally in organ culture. Gelatinase B-deficient mice were bred with Col4a3-/- mice, a model for Alport syndrome, to determine whether gelB influences the progression of glomerulonephritis. This is an important question, as it has been hypothesized that proteases are involved in damaging Alport glomerular basement membrane. However, the presence or absence of gelB did not affect the rate of progression of renal disease. Thus, gelB does not have a discernible role in the normal kidney and gelB is not involved in the progression of glomerulonephritis in a mouse model of Alport syndrome.

Animals↗
PubMed2000

Confrontation naming of environmental sounds.

The development of a set of everyday, nonverbal, digitized sounds for use in auditory confrontation naming applications is described. Normative data are reported for 120 sounds of varying lengths representing a wide variety of acoustic events such as sounds produced by animals, people, musical instruments, tools, signals, and liquids. In Study 1, criteria for scoring naming accuracy were developed and rating data were gathered on degree of confidence in sound identification and the perceived familiarity, complexity, and pleasantness of the sounds. In Study 2, the previously developed criteria for scoring naming accuracy were applied to the naming responses of a new sample of subjects, and oral naming times were measured. In Study 3 data were gathered on how subjects categorized the sounds: In the first categorization task - free classification - subjects generated category descriptions for the sounds; in the second task - constrained classification - a different sample of subjects selected the most appropriate category label for each sound from a list of 27 labels generated in the first task. Tables are provided in which the 120 stimuli are sorted by familiarity, complexity, pleasantness, duration, naming accuracy, speed of identification, and category placement. The. WAV sound files are freely available to researchers and clinicians via a sound archive on the World Wide Web; the URL is http://www.cofc.edu/~marcellm/confront.htm.

Acoustic Stimulation↗
PubMed2000

Winding roads and faded signs: ethical decision making in a postmodern world.

We are living in an era, sometimes referred to as "postmodern," exemplified by complex change related to vast increases in information and technology and exposure to diverse people and ideas. Society as a whole is experiencing dissonance in solving ethical dilemmas, and nurses' ethical dilemmas are never far removed from the social context in which nurses practice. This article explores aspects of postmodernism that complicate ethical decision making. It is hoped that this discussion may aid nurses in understanding how world values, especially those of postmodernism, complicate ethical decision making in health care. Suggestions melding aspects of the postmodern with traditional approaches to ethical decision making are presented.

Bioethics↗
PubMed2000

Significance of minimal or no intraperitoneal fluid visible on CT scan associated with blunt liver and splenic injuries: a multicenter analysis.

BACKGROUND: The use of ultrasound (U/S) for the evaluation of patients with blunt abdominal trauma is gaining increasing acceptance. Patients who would have undergone computed tomographic (CT) scan may now be evaluated solely with U/S. Solid organ injuries with minimal or no free fluid may be missed by surgeon sonographers. OBJECTIVE: The purpose of this study was to describe the incidence and clinical importance of liver and splenic injuries with minimal or no free intraperitoneal fluid visible on CT scan. We hypothesized that these solid organ injuries occur infrequently and are of minor clinical significance. METHODS: Patient records and CT scans were reviewed for the presence of and outcome associated with blunt liver and splenic injuries with minimal (<250 mL) or no free fluid detected by an attending radiologist. Data were collected from six major trauma centers during a 4-year period before the introduction of U/S and included demographics, grade of injury (American Association for the Surgery of Trauma scale), need for operative intervention, and outcome. RESULTS: A total of 938 patients with liver and splenic injuries were identified. In this group, 11% of liver injuries and 12% of splenic injuries had no free fluid visible on CT scan and could be missed by diagnostic peritoneal lavage or U/S. Of the 938 patients, 267 (28%) met the inclusion criteria; 161 had injury to the spleen and 125 had injury to the liver. In the 267 patients studied, 97% of the injuries were managed nonoperatively. However, 8 patients (3%) required operative intervention for bleeding. Compared with the liver, the spleen was significantly more likely to bleed (p = 0.01), but the grade of splenic injury was not related to the risk for hemorrhage (p = 0.051). CONCLUSION: Data from this study suggest that injuries to the liver or spleen with minimal or no intraperitoneal fluid visible on CT scan occur more frequently than predicted but usually are of minimal clinical significance. However, patients with splenic injuries may be missed by abdominal U/S. We found a 5% associated risk of bleeding. Therefore, abdominal U/S should not be used as the sole diagnostic modality in all stable patients at risk for blunt abdominal injury.

Adult↗
PubMed2000

Transfusion-related acute lung injury associated with interdonor incompatibility for the neutrophil-specific antigen HNA-1a.

BACKGROUND AND OBJECTIVES: A patient transfused with two pooled platelet concentrates became breathless. Bilateral infiltrates were seen on chest X-ray. A diagnosis of transfusion-related acute lung injury (TRALI) was made. The patient received 100% oxygen and recovered after 5 days. MATERIALS AND METHODS: Antibody screening, cross-matching for granulocyte and lymphocyte antibodies and typing for granulocyte antigens was undertaken. RESULTS: The patient typed as HNA-1b/HNA-1b. Granulocyte and lymphocyte antibodies were not detected in the patient's serum or in any of the donor sera by cross-match. In antibody screening against typed panel granulocytes, complement-fixing anti-HNA-1a IgM antibodies were detected in the serum of one female donor. Two of the other donors who contributed to the pooled platelet concentrate containing the HNA-1a IgM antibodies typed as HNA-1a/HNA-1b. CONCLUSION: Anti-HNA-1a IgM antibodies may have formed immune complexes with white cell fragments or soluble FcgammaRIII from HNA-1a+ donors in the pooled platelet concentrate and initiated TRALI.

Adult↗
PubMed2000

Larval growth of Diaprepes abbreviatus (Coleoptera: Curculionidae) and resulting root injury to three citrus varieties in two soil types.

Larval growth and intraspecific competition of Diaprepes abbreviatus (L.) larvae and consequent root injury in container-grown citrus in the greenhouse were evaluated. Roots of Carrizo citrange, Citrus sinesis L. Osbeck x Poncirus trifoliata (L.) Raf.; Cleopatra mandarin, C. reticulata Blanco, and Swingle citrumelo, C. paradisi Macf. x P. trifoliata (L.) Raf. rootstock seedlings grown in Candler fine sand and potting soil were colonized with different populations of D. abbreviatus larvae. Larvae were exposed to the seedlings for 79 d. Larval growth and development increased steadily for approximately 70 d on all rootstock-soil combinations, at which time most larvae were instars 6-8. Most feeding injury occurred to roots when larvae were between instars 3 and 6. Larval weight reached a plateau at approximately 70 d, but often declined between 70 and 79 d. When larvae were small, injury to seedlings developed slowly, primarily on fibrous roots, then feeding increased rapidly, often resulting in total consumption of both fibrous root and bark tissue. Although not statistically significant, root injury developed slightly slower on Swingle citrumelo compared with Carrizo and Cleopatra rootstocks, but damage was comparable by 79 d. Little or no difference in consumptive benefit to the larvae was found between the rootstocks. Based on larval weight days, little feeding injury occurred during the first 21 d, but increased rapidly between 21 and 60 d. Soil type affected the rate of larval growth and development, with potting soil contributing to greater growth rates. Detritus in potting soil provided little or no nutritional resource, suggesting that the effect of potting soil on larval development was primarily physical. In addition, fewer inoculated larvae per seedling exhibited greater weight gains than higher infestation densities, suggesting that intraspecific competition for nutritional resources influenced larval development.

Animals↗
PubMed2000

Pre-operative evaluation of the lower extremity prior to microvascular free fibula flap harvest.

The microvascular free fibula flap, is currently one of the preferred methods for reconstruction of the oromandibular defect. The patency of the major vessels in the donor limb should be evaluated before the fibula is harvested because the blood supply can be inadequate to safely utilise this flap. The best method of evaluating, pre-operatively, the lower limb vasculature is controversial. Femoral angiography has been considered as the gold standard, however, the current literature advocates less invasive methods of assessment such as magnetic resonance angiography and colour flow Doppler. A postal questionnaire was sent to all members of The British Association of Head and Neck Oncologists asking details of the preferred method of lower limb vascular assessment prior to fibula flap harvest. Of 137 responses, 48 performed free fibula flaps. Of these 48 surgeons, the preferred method for evaluation was palpation of pulses combined with either angiography (40%) or Doppler on the ward (38%). None of this subgroup of surgeons utilised colour flow Doppler as a first line investigation despite this being available to 67% of responders. This survey highlights the diversity in pre-operative assessment amongst surgeons performing fibula flaps for head and neck malignancy. Few relied on clinical examination alone; however, the less invasive methods of vascular imaging were seldom utilised.

Bone Transplantation↗
PubMed2000

Evaluation of a direct doctor-patient telephone advice line in general practice.

A general practitioner-staffed direct access telephone advice line was made available for 30 minutes every morning at an inner-London practice to advise patients with urgent problems. Users valued the service, but the impact on surgery consultations was too small for this to be advocated as an alternative to emergency consultations.

Family Practice↗
PubMed1999

General practitioners' perceptions of effective health care.

OBJECTIVES: To explore general practitioners' perceptions of effective health care and its application in their own practice; to examine how these perceptions relate to assumptions about clinicians' values and behaviour implicit in the evidence based medicine approach. DESIGN: A qualitative study using semistructured interviews. SETTING: Eight general practices in North Thames region that were part of the Medical Research Council General Practice Research Framework. PARTICIPANTS: 24 general practitioners, three from each practice. MAIN OUTCOME MEASURES: Respondents' definitions of effective health care, reasons for not practising effectively according to their own criteria, sources of information used to answer clinical questions about patients, reasons for making changes in clinical practice. RESULTS: Three categories of definitions emerged: clinical, patient related, and resource related. Patient factors were the main reason given for not practising effectively; others were lack of time, doctors' lack of knowledge and skills, lack of resources, and "human failings." Main sources of information used in situations of clinical uncertainty were general practitioner partners and hospital doctors. Contact with hospital doctors and observation of hospital practice were just as likely as information from medical and scientific literature to bring about changes in clinical practice. CONCLUSIONS: The findings suggest that the central assumptions of the evidence based medicine paradigm may not be shared by many general practitioners, making its application in general practice problematic. The promotion of effective care in general practice requires a broader vision and a more pragmatic approach which takes account of practitioners' concerns and is compatible with the complex nature of their work.

Adult↗
PubMed1999

Answers to unasked questions: writing in the margins.

This qualitative study is a secondary analysis of comments spontaneously provided by participants in a quantitative survey. Narrative comments were written by 25% (n = 205) of the adults with multiple sclerosis who responded to the survey. Forms of unsolicited written comments included responses to questions written in the margins of the questionnaires and narratives on blank booklet pages. The purpose of this study was to apprehend what participants were telling us, particularly in the responses that they had written in the margins. Qualitative methods were used to identify and explore major categories in the participants' comments. Those who wrote unsolicited comments perceived their economic resources as less adequate, were experiencing greater family and social demands related to their illness, and were more likely to live in a nonmetropolitan county than other respondents. Secondary analysis of this rich qualitative data enhances the depth of our understanding of the person's experience with chronic illness.

Adaptation, Psychological↗
PubMed1999

Radiofrequency ablation lesions in a pig liver model.

BACKGROUND: Radiofrequency (RF) ablation has been reported as a means of liver tumor destruction. This study evaluates the use of ultrasound monitoring of radiofrequency lesion creation and describes the morphology, histologic characteristics, and vascular effects of radiofrequency ablations in a pig liver model. MATERIALS AND METHODS: Hemodynamic monitoring was established and laparotomies were performed in 50-kg pigs. Under ultrasound guidance, radiofrequency needle probes were placed in the liver at predetermined locations. Radiofrequency energy was applied over 15 min to generate lesions 3 cm in diameter. Eighty lesions were generated in 10 animals. At the completion of the experiment, the lesions were examined with ultrasound and then excised for CT, gross, and histologic examination. RESULTS: There were no adverse systemic effects. Ultrasound imaging demonstrated the size, shape, and position of the lesions. Gross examination demonstrated a core of ablated tissue with a surrounding 1- to 2-mm hemorrhagic perimeter. Lesion volumes averaged 12.8 cc(3) (range 5-34 cc(3)). Final lesion shape and size were frequently altered by the cooling effect of local blood flow. Histologic stains demonstrated microvascular thrombosis and coagulative necrosis within the lesions. There appeared to be 100% cellular destruction within the lesion by cytochemical staining. CONCLUSIONS: We demonstrated that RF ablation is capable of killing large volumes of normal liver tissue; however, local vasculature plays a significant a role in defining the ultimate size and shape of the lesion created. This may interfere with the utility of radiofrequency ablation as a modality for local tumor control.

Animals↗